Background: The monoamine oxidase (MAO)
inhibitor selegiline has demonstrated antidepressant efficacy
superior to placebo. A selegiline transdermal system (STS) has
been developed with unique pharmacokinetic and pharmacodynamic
properties that allow inhibition of central nervous system MAO-A
and MAO-B enzymes while substantially avoiding inhibition of
intestinal and liver MAO-A enzyme. This novel transdermal system
provides targeted MAO inhibition without clinically significant
increases in sensitivity to dietary tyramine. We investigated the
safety and efficacy of STS in patients with major depressive
disorder.

Method: 365 outpatients 18 to 65 years old with
a DSM-IV diagnosis of major depressive disorder were enrolled at
16 sites. A 17-item Hamilton Rating Scale for Depression
(HAM-D-17) score of >=20 was required for entry. Patients were
randomly assigned to receive either STS,20 mg/20 cm2,
daily or placebo patch for up to 8 weeks. A tyramine-restricted
diet was neither required nor advised. Efficacy, safety, and
vital sign measures were obtained regularly.

Results: 289 patients were randomly assigned to
treatment and received at least 1 on-therapy evaluation (STS, N =
145; placebo, N = 144). Although the effect size was modest, at
endpoint, STS was statistically superior to placebo on the MADRS
(p = .001) and HAM-D-28 ( p = .039) ratings and showed a
nonsignificant superiority on the HAM-D-17 (p = .069) and
Clinical Global Impressions-Severity ratings (p < .055). Side
effect profiles were similar for STS and placebo with the
exception of application-site reaction, which was observed in
31.5% of STS patients and 15.1% of placebo-treated patients (p =
.001). No significant differences were observed in blood pressure
measures between treatment groups.

Conclusion: Results from this double-blind,
placebo-controlled clinical trial demonstrate that STS may have a
modest, but statistically significant, antidepressant benefit
compared with placebo and a similar safety profile compared with
placebo in the absence of a tyramine-restricted diet.